Target shape portion cutting apparatus, robot equipped with the apparatus and target shape portion cutting method

ABSTRACT

With a metal sheet formed with a target shape portion, a remaining portion surrounding the target shape portion and elongated joint portion(s) joining the target shape portion with the remaining portion, the apparatus cuts out the target shape portion from the metal sheet by shearing the joint portion at a region bordering on the target portion to cut out the target shape portion. The apparatus comprises a movable blade member designed to move to a position below the joint portion and a fixed blade member for pressing the joint portion from above. The apparatus, being placed at a fixed position, rotates or linearly moves the movable blade member with respect to the fixed blade member to shear the joint portion at a region bordering on the target portion and bend a sheared-side end of the sheared joint portion upward.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention:

[0002] This invention relates to a target shape portion cuttingapparatus and method of cutting out a target shape portion formed on ametal sheet from the remaining portion thereof, and a robot equippedwith the target shape portion cutting apparatus.

[0003] 2. Description of the Prior Art:

[0004] For cutting out a target shape portion from a metal sheet, themetal sheet is first worked so that the target shape portion, a portionsurrounding the target shape portion (the surrounding portion beinghereinafter called “base metal sheet”) and at least one elongated jointportion for joining the former two portions are formed on the metalsheet, and then the joint portion is cut out, using:

[0005] (a) a method of mechanically applying an impact or vibration to aportion near the joint portion to thereby cause plastic deformation sothat a link portion between the target shape portion and the base metalsheet is cut out;

[0006] (b) a method of cutting out the target shape portion by afinishing machine without leaving any joint portion, and drop the targetshape portion on a conveyor or the like for collection of the targetshape portion; or

[0007] (c) a method of using a robot mounting a target shape portioncutting apparatus equipped with a scissors-like tool (nipper), whichcauses the tool to approach vertically to the joint portion between thetarget shape portion and the base metal sheet, from above, so that theblade of the tool abuts on the top surface of the joint portion tothereby snip off the joint portion in the plane direction.

[0008] Since the above method (a) applies an impact or vibration to thejoint portion, burrs are produced on the portion where the target shapeportion has been cut out. Therefore, post processing, such as burrremoval, is therefore needed after separating the target shape portion.Further, since the position and posture of the target shape portionafter separation are not stable, it is difficult for the robot to holdand take away the cut-out target shape portion. This makes it difficultto achieve automation of working metal sheets, remote manipulation ofthe robot and so forth.

[0009] The above method (b) likewise causes unstable position andposture of the target shape portion after it is cut out. Therefore, likethe method (a), the method (b) makes it difficult for the robot to holdand take away the cut-out target shape portion. This makes it difficultto achieve automation of working metal sheets, remote manipulation ofthe robot and so forth.

[0010] Since the above method (c) cuts out the joint portion formed onthe metal sheet by the tool, such as the nipper, a hole large enough forallowing the free end of the tool to enter has to be formed in an areaaround the joint portion of the metal sheet. Further, since the tool(nipper) moves in the widthwise direction of the joint portion to cutout the joint portion, a part of the joint portion remains on thecut-out target shape portion. Therefore this method requirespost-processing for removing the remaining portion of the joint portion.Further, separation of the target shape portion cannot be confirmedbased on only the tool movement. Moreover, it is difficult to take out acut-out target portion because a portion of the joint portion remainingon the target shape portion may interfere with a portion of the jointportion remaining on the base metal sheet when cutting out and takingout the target shape portion. In addition, as the free end of the toolgoes through a tool insertion hole formed in the metal sheet andprotrudes further below the bottom surface of the metal sheet when thetarget shape portion is cut out, the tool may cut the member whichsupports the metal sheet.

OBJECTS AND SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide a target shapeportion cutting apparatus and method that are designed in such a mannerthat when a target shape portion formed on a metal sheet is cut out fromthe remaining portion of the metal sheet, the results of the separationrequire no post-processing and do not interrupt taking out of a cut-outtarget shape portion.

[0012] To achieve the abovementioned object, with a metal sheet whichhas been worked in such a way that a target shape is connected to a basemetal through one or a plurality of joint portions by forming a hole ata region adjacent to the joint portion, a target shape portion cuttingapparatus according to one aspect of the present invention comprises afirst member having a first blade for pressing a boundary portionbetween the target shape portion and the joint portions of theperforated metal sheet from one face of the perforated metal sheet andfrom the side of the target shape portion; and a second member having asecond blade which approaches the joint portion from the other face ofthe perforated metal sheet, grips the boundary portion in associationwith the first blade in a thickness direction of the perforated metalsheet and shears the perforated metal sheet at the boundary portion tothereby cut the target shape portion off a joint portion.

[0013] The second member having the second blade is supported in amanner such that it rotates relative to the first member having thefirst blade and is driven by a cylinder or a motor. Alternatively, thesecond member having the second blade is moved by a cylinder or a motorin the thickness direction of the perforated metal sheet relative to thefirst member having the first blade and cuts the target shape portionoff a joint portion. The second member having the second blade is thickenough to be able to bend a joint portion by pushing it at the time ofcutting out the target shape portion from the joint portion.

[0014] A robot may mount the target shape portion cutting apparatus tocut a target shape portion of a metal sheet off a joint portion whichconnects the target shape portion to a base metal sheet.

[0015] A method of cutting out a target shape portion from a base metalsheet using the robot comprises a step of placing a metal sheet havingthe target shape portion connected to the base metal sheet with one or aplurality of joint portions on a mounting section whose surface memberis made of a soft material or a brush-like material soft enough to beable to keep a plane posture of the target shape portion and the basemetal sheet; a step of pressing an exposed region of the mountingsection with the second member having the second blade through a toolinsertion hole formed adjacent to the target shape portion to be cutout; a step of moving the second blade under the joint portion to be cutout from the target shape portion while pressing the mounting sectionwith the second member having the second blade; a step of pressing aboundary portion between the target shape portion and the joint portionwith the first blade positioned above the joint portion, from the sideof the target shape portion; and a step of moving the second bladeupward to snip off the joint portion in association with the firstblade.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The foregoing and other objects and features of the inventionwill become apparent from the following description of preferredembodiments of the invention with reference to the accompanying drawingsin which:

[0017]FIG. 1 is a perspective view exemplifying a robot mounting atarget shape portion cutting apparatus according to a first embodimentof the present invention;

[0018]FIG. 2A is a side view of the target shape portion cuttingapparatus in FIG. 1;

[0019]FIG. 2B is a partly enlarged view (front view) of the target shapeportion cutting apparatus in FIG. 2A;

[0020]FIG. 3 is a diagram showing an example of a worked metal sheet inwhich a target shape portion formed is connected to a base metal sheetwith joint portions;

[0021]FIG. 4 is a diagram for explaining procedures of cutting out atarget shape portion;

[0022]FIG. 5 is a diagram for explaining an operation of cutting out atarget shape portion from the worked metal sheet shown in FIG. 3, inwhich a movable blade member of the target shape portion cuttingapparatus is in a position just to start entering a tool insertion holeformed in the metal sheet;

[0023]FIG. 6 is a diagram showing the movable blade member inserted inthe tool insertion hole from the position in FIG. 5;

[0024]FIG. 7 is a diagram showing the movable blade member positionedready to cut out a joint portion after moving from a position in FIG. 6toward the joint portion;

[0025]FIG. 8 is a diagram showing the movable blade member which hasjust sheared the joint portion after pivoting from the position in FIG.7;

[0026]FIG. 9 is a diagram depicting the worked metal sheet with thejoint portion sheared;

[0027]FIG. 10A is a side view of a target shape portion cuttingapparatus according to a second embodiment of the present invention inwhich a second blade is open with respect to a first blade;

[0028]FIG. 10B is a partly enlarged view (front view) of the targetshape portion cutting apparatus in FIG. 10A; and

[0029]FIG. 11 is a side view of the target shape portion cuttingapparatus in FIGS. 10A in which the second blade is closed with respectto the first blade.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] A target shape portion cutting apparatus according to the firstembodiment of the present invention will now be described with referenceto FIGS. 1 through 9.

[0031]FIG. 1 exemplifies a robot 2 equipped with a target shape portioncutting apparatus 1 according to the embodiment. The robot 2 comprises arotary body 4 which rotates around the vertical axis with respect to abase 3, a first arm 5 mounted on the rotary body 4, a second arm 6attached to the distal end of the first arm 5, and a wrist 7 connectedto the distal end of the second arm 6. The first arm 5 turns around thehorizontal axis. The second arm 6 likewise turns around the horizontalaxis. The wrist 7 rotates around three axes perpendicular to oneanother.

[0032] The target shape portion cutting apparatus 1 is attached to thewrist 7 of the robot 2 via an automatic tool changer 8. The automatictool changer 8 has a robot-side mounting member 8 a to be attached tothe flange surface of the wrist 7 and a tool-side mounting member 8 b tobe attached to the tool side (i.e., to the target shape portion cuttingapparatus 1 in the embodiment). Various tools including the target shapeportion cutting apparatus 1 may be attached to or detached from thewrist 7 of the robot 2 by connecting or disconnecting the robot-sidemounting member 8 a and the tool-side mounting member 8 b of theautomatic tool changer 8 to or from the flange surface of the wrist 7and the tool attached to the wrist 7.

[0033]FIG. 2A is a side view of the target shape portion cuttingapparatus 1, and FIG. 2B is a partial front view for explaining how tocut a joint portion between a target shape portion and a base metalsheet with the target shape portion cutting apparatus 1 in FIG. 2A.

[0034] The target shape portion cutting apparatus 1 has an attachmentmember 10 and a tool frame 11 secured to the attachment member 10. Theattachment member 10 is used to attach the target shape portion cuttingapparatus 1 to the automatic tool changer 8 shown in FIG. 1. A fixedblade member 21 having a first blade 21 a (fixed cutting blade) issecured to the lower end of the tool frame 11. A pressing block 16 (FIG.2B) which presses a target shape portion formed on a metal sheet fromabove is fixed to a side of the tool frame 11 opposite the side wherethe fixed blade member 21 is secured.

[0035] A movable blade member 22 having a second blade 22 a (movablecutting blade) at one end thereof is rotatably attached to a pin 25which protrudes from the side surface of the tool frame 11. As thesecond blade 22 a rotates with respect to the first blade 21 a, a jointportion which connects the target shape portion to the base metal sheetis cut to separate the target shape portion from the base metal sheet.

[0036] The first blade 21 a and the second blade 22 a, which are bothsuper steel chips available on the market, are respectively mounted onthe fixed blade member 21 and the movable blade member 22 in areplaceable manner. As will be discussed later, the movable blade member22 is thick enough to be able to bend a portion near the cut surface ofa joint portion when its second blade 22 a turns and cuts the jointportion in association with the first blade 21 a.

[0037] A drive cylinder 12 is attached to the tool frame 11. The drivecylinder 12 uses air pressure, hydraulic pressure or a drive source suchas a motor or a servo motor. A pin 23 provided at the distal end of arod 13 of the drive cylinder 12 is engaged with an elongated hole 24formed in an end portion of the movable blade member 22 opposite the endwhere the second blade 22 a is attached. Since the drive cylinder 12 isactuated, therefore, the movable blade member 22 rotates around the pin25 so that the second blade 22 a is closed with respect to the firstblade 21 a, thereby cutting a joint portion between the target shapeportion and the base metal sheet, as will be discussed later.

[0038] A dog 14 is attached to the rod 13 of the drive cylinder 12. Apair of proximity switches 15 a and 15 b are attached to the tool frame11 at positions above and below the dog 14. When the rod 13 movesdownward and the second blade 22 a is closed with respect to the firstblade 21 a, the dog 14 contacts the lower proximity switch 15 b,indicating that the second blade 22 a is closed with respect to thefirst blade 21 a. When the rod 13 moves upward and the second blade 22 ais open with respect to the first blade 21 a, the dog 14 contacts theupper proximity switch 15 a, indicating that the second blade 22 a isopen with respect to the first blade 21 a.

[0039] A metal sheet 30 having a joint portion which is to be cut by theopening/closing action of the second blade 22 a with respect to thefirst blade 21 a is placed on a mounting section 27 as shown in FIG. 2A.

[0040] With reference to FIGS. 3 through 9, a description will now begiven of an operation of shearing and cutting a joint portion between atarget shape portion and a base metal sheet formed on a metal sheetusing the target shape portion cutting apparatus 1.

[0041] As shown in FIG. 3, holes 34 are formed in right and left sidesof each joint portion 33 between the target shape portion 31 and thebase metal sheet 32 of a metal sheet 30. This holes 34 has apredetermined width and a predetermined length where the movable blademember 22 is inserted. In the embodiment in FIG. 3, one target shapeportion 31 is connected to the base metal sheet 32 with two jointportions 33. Reference numeral 35 denotes a boundary line between thetarget shape portion 31 and each joint portion 33. The joint portion 33is cut along the boundary line 35 by the rotation of the second blade 22a with respect to the first blade 21 a, as will be discussed later.

[0042]FIG. 4 illustrates procedures of cutting the joint portion 33between the target shape portion 31 and the base metal sheet 32 in themetal sheet 30.

[0043] A metal sheet is worked into a shape as shown in FIG. 3 and theworked metal sheet 30 is picked up and taken out by the robot 2 andsecurely placed on the mounting section 27 of a work table (steps 100and 101). The mounting section 27 is made of a material, such as a brushand sponge rubber, soft enough to be able to keep a plane posture of themetal sheet 30 as shown in FIG. 2A.

[0044] Next, the metal sheet 30 placed on the mounting section 27 isphotographed with a camera (not shown) and the image is subjected toimage processing in an image processor (not shown) to acquire the amountof positional deviation from the reference position of the metal sheet30. Based on the amount of positional deviation, position correctiondata is acquired. A robot control apparatus receives the positioncorrection data from the image processor (step 102). The robot controlapparatus then obtains the shearing position (the boundary line 35between the target shape portion 31 and the joint portion 33) based onthe received position correction data to generate robot manipulationdata (step 103).

[0045] Meanwhile, a tool for holding the metal sheet 30 is detached fromthe wrist 7 of the robot 2 using the automatic tool changer 8 and thetarget shape portion cutting apparatus 1 is attached to the wrist 7 asshown in FIG. 1.

[0046] Since the robot 2 is manipulated based on the robot manipulationdata obtained in step 103, the target shape portion cutting apparatus 1shears the joint portion 33 and cuts out the target shape portion 31from the base metal sheet 32 (step 104). The details of the cuttingoperation will be given later.

[0047] Finally, the target shape portion cutting apparatus 1 is detachedfrom the wrist 7 of the robot 2 and a tool for grasping the target shapeportion 31 is attached to the wrist 7. Then, the tool holds the targetshape portion 31 and takes the target shape portion out for placement ata predetermined position in a predetermined posture (step 105).

[0048] The above explanation is of the outline of the procedures forcutting out the target shape portion 31 from the worked metal sheet 30and taking out the target shape portion 31.

[0049] Referring now to FIG. 2 and FIGS. 5 to 9, a detailed descriptionwill be given of the operation of cutting out a target shape portion byshearing the joint portion 33 in step 104 in FIG. 4.

[0050]FIG. 5 shows the state where the distal end of the movable blademember 22 of the target shape portion cutting apparatus 1 just startsentering the tool insertion hole 34 of the worked metal sheet 30.

[0051]FIG. 6 shows the state where the distal end of the movable blademember 22 is inserted into the tool insertion hole 34 while being openwith respect to the fixed blade member 21. The state where the movableblade member 22 is open with respect to the fixed blade member 21 can bedetected by the dog 14 and the proximity switch 15 a.

[0052] The worked metal sheet 30 is securely placed on the top surfaceof the mounting section 27 made of a soft material such as brush orsponge rubber. This allows the second blade 22 a of the movable blademember 22 to pass through the tool insertion hole 34 of the metal sheet30 and go further down below the bottom surface of the joint portion 33while deforming the brush, sponge rubber or the like of the mountingsection 27.

[0053] The target shape portion cutting apparatus 1 whose movable blademember 22 is positioned in the tool insertion hole 34 as shown in FIG. 6is moved in the widthwise direction of the metal sheet 30 toward thejoint portion 33. During the movement of the target shape portioncutting apparatus 1, the movable blade member 22 slides on the mountingsection 27.

[0054] The movement of the target shape portion cutting apparatus 1causes one side of the movable blade member 22 to closely contact theside edge of the target shape portion 31. At the same time, the targetshape portion cutting apparatus 1 presses the fixed blade member 21 andthe pressing block 16 against the top surface of the target shapeportion 31 so that the edge line of the first blade 21 a of the fixedblade member 21 comes over the boundary line 35.

[0055] This completes the positioning of the target shape portioncutting apparatus 1 with respect to the worked metal sheet 30. FIG. 7shows the state in which the positioning is completed.

[0056] Next, the drive cylinder 12 of the target shape portion cuttingapparatus 1 is driven to turn the movable blade member 22 at theposition and in the posture shown in FIG. 7 around the pin 25 to engagethe first blade 21 a of the fixed blade member 21 with the second blade22 a of the movable blade member 22 and shear the joint portion 33 atthe boundary line 35 between the joint portion 33 and the target shapeportion 31, as shown in FIG. 8. As the target shape portion 31 ispressed by the fixed blade member 21 and the pressing block 16 whileshearing the joint portion 33, the target shape portion 31 is not movedby this shearing operation (or by the rotation of the movable blademember 22). The rotation of the movable blade member 22 up to the lastposition or the complete engagement of the first blade 21 a with thesecond blade 22 a is detected and checked by the proximity switch 15 b.

[0057] After shearing the joint portion 33, the movable blade member 22rotates further upward and passes through a clearance between the endface of the cut joint portion 33 and the side end face of the targetshape portion 31. Since the movable blade member 22 has a predeterminedthickness (greater than the clearance) as mentioned above, however, themovable blade member 22 interferes with the joint portion 33 and bendsthe sheared-side end of the joint portion 33 upward as the movable blademember passes through the clearance.

[0058] As a result, the joint portion 33 remaining on the side of thebase metal sheet 32 is kept curved as shown in FIG. 9. Therefore, whenpicking up the target shape portion 31 in FIG. 9 to take out the targetshape portion from the worked metal sheet 30, the target shape portion31 does not interfere with the sheared-side end of the joint portion 33.

[0059] As described above, the second blade 22 a of the movable blademember 22 moves in the direction of the thickness of the sheet relativeto the first blade 21 a of the fixed blade member 21 and cuts the jointportion 33 at the boundary line 35 between the joint portion 33 and thetarget shape portion 31, so that burrs does not occur on the shearedsurface on the side of the target shape portion 31. In addition, whenpicking up and taking out the sheared target shape portion 31 aftershearing of the joint portion 33, the target shape portion 31 does notcontact the sheared joint portion 33. Further, during shearing of thejoint portion 33, the position and posture of the target shape portion31 do not change. Since the movable blade member 22 passes through thetool insertion hole 34 to deform the brush, sponge rubber or the likethat constitutes the mounting section 27 on which the metal sheet 30 isplaced, the brush, sponge rubber or the like is not cut with the forwardmovement and the rotation of the movable blade member 22.

[0060] According to the above-described embodiment, the work of cuttingout a target shape portion (see FIG. 4) is carried out by a single robotto which tools, such a hand for holding the metal sheet 30 and thetarget shape portion 31 and the target shape portion cutting apparatus1, are attached for the work. Alternatively, a plurality of robots maybe used to individually perform the work of holding and carrying themetal sheet 30 and the target shape portion 31 and the work of cuttingout the target shape portion 31.

[0061] In place of the pressing block 16, an adsorption pad may be usedto adsorb and press the target shape portion 31 of the metal sheet 30,so that, after shearing of the joint portion 33, the target shapeportion 31 adsorbed by the adsorption pad is taken out and conveyed to apredetermined position.

[0062] A target shape portion cutting apparatus 1′ according to thesecond embodiment of the present invention will be discussed below withreference to FIGS. 10A, 10B and 11.

[0063] According to the embodiment, the second blade or the movableblade moves (up and down) while maintaining its posture with respect tothe first blade or the fixed blade, so that the joint portion 33 betweenthe target shape portion 31 and the base metal sheet 32 in the workedmetal sheet is sheared.

[0064] The target shape portion cutting apparatus 1′ has an attachmentmember 40 and a tool frame 41 secured to the attachment member 40. Theattachment member 40 is used to attach the target shape portion cuttingapparatus 1′ to the automatic tool changer 8 shown in FIG. 1.

[0065] A drive cylinder 42 is attached to the tool frame 41. A fixedblade member 46 is attached to the lower end of the tool frame 41. Amovable blade member 47 is attached to a rod 43 of the drive cylinder 42via a link member 44. A first blade 46 a as a fixed blade is attached tothe fixed blade member 46, and a second blade 47 a as a movable blade isattached to the movable blade member 47.

[0066] When the drive cylinder 42 is actuated to move the rod 43 in thedirection of the axial center, the movable blade member 47 moves in theup-and-down direction while being guided by a guide 45 provided on thetool frame 41. FIG. 10A (and FIG. 10B being an enlarged view of FIG.10A) shows the state where the rod 43 of the drive cylinder 42 movesdownward so that the movable blade member 47 (second blade 47 a) is openwith respect to the fixed blade member 46 (first blade 46 a). FIG. 11shows the state where the movable blade member 47 (second blade 47 a) isclosed (engaged) with respect to the fixed blade member 46 (first blade46 a).

[0067] A pressing block 48 which presses a target shape portion formedon a metal sheet from above is secured to the side of the tool frame 41opposite the side where the fixed blade member 46 is securely attached.

[0068] The work of cutting the joint portion 33 in the worked metalsheet 30 shown in FIG. 3 using the target shape portion cuttingapparatus 1′ of the embodiment is almost the same as the work of cuttingthe joint portion 33 using the target shape portion cutting apparatus 1of the first embodiment as explained above. The procedures of the workwill be discussed below.

[0069] The target shape portion cutting apparatus 1′ is attached to therobot 2. With the second blade 47 a set open with respect to the firstblade 46 a as shown in FIG. 10, the distal end of the movable blademember 47 is inserted in to the tool insertion hole 34 of the workedmetal sheet 30.

[0070] The target shape portion cutting apparatus 1′ is moved forward tothe position where the first blade 46 a and the second blade 47 asandwich the joint portion 33 from above and below.

[0071] One side face of the movable blade member 47 is positioned inclose contact with the associated side end face of the target shapeportion 31 in the metal sheet 30. At the same time, the fixed blademember 46 and the pressing block 48 are pressed against the top surfaceof the target shape portion 31 in such a way that the edge line of thefirst blade 46 a of the fixed blade member 46 comes over the boundaryline 35 between the joint portion 33 and the target shape portion 31.

[0072] The drive cylinder 42 is actuated to lift the movable blademember 47 above with respect to the fixed blade member 46 as shown inFIG. 11, so that the joint portion 33 is sheared at the boundary line 35by the cooperation of the first blade 46 a and the second blade 47 a.

[0073] As shearing of the joint portion 33 using the target shapeportion cutting apparatus 1′ of the second embodiment is executed bymoving the second blade 47 a of the fixed blade member 47 in thedirection of the thickness of the metal sheet 30, in the same manner asin the shearing of the joint portion 33 using the target shape portioncutting apparatus 1 of the first embodiment, burr does not occur on thesheared surface of the target shape portion 31. Since the movable blademember 47 has a predetermined thickness, the movable blade member 47contacts the joint portion 33 and bends the sheared-side end of thejoint portion 33 upward as the movable blade member shears the jointportion 33 and moves further upward, in the same way as in the case ofthe first embodiment. Therefore, when picking up and taking out thetarget shape portion 31 after shearing the joint portion 33, the targetshape portion 31 does not interfere with the sheared joint portion 33.This facilitates the taking out operation of the target shape portion31. During shearing of the joint portion 33, the target shape portion 31is kept pressed by the fixed blade member 46 and the pressing block 48,thus preventing the target shape portion 31 from being moved by theshearing operation (the up and down movement of the movable blade member47).

[0074] Since the movable blade member 47 passes through the toolinsertion hole 34 to deform the brush, sponge rubber or the like thatconstitutes the mounting section 27 on which the metal sheet 30 isplaced, the sponge rubber or the brush is not cut with the forwardmovement and the rotation of the movable blade member 47, in the sameway as in the case of the first embodiment.

[0075] In short, as the target shape portion cutting apparatus accordingto the present invention shears a joint portion between the base metalsheet and the target shape portion in the direction of the thickness ofthe joint portion, burr does not cause so that no post-processing isrequired.

[0076] Since the cut end face of the joint portion does not contact orinterfere with the end face of the target shape portion after shearingof the joint portion, it is easy to take out the cut-out target shapeportion. This facilitates the automation of the robot-based metal sheetworking. Further, as the mounting section on which the metal sheet isplaced is not cut by the shearing of the joint portion, longer servicelife of the mounting section can be expected. Further, as the targetshape portion, even when it has bee cut out, staying on the mountingsection without dropping below, it becomes easier to collect and alignindividual target shape portions. In addition, it is easy toautomatically collect and align individual base metal sheets from whichtarget shape portions have been cut out.

What is claimed is:
 1. A target shape portion cutting apparatus forcutting a target shape portion off a joint portion in a metal sheetwhich has been worked such that the target shape is connected to a basemetal through one or a plurality of joint portions by forming a hole ata region adjacent to the joint potion, comprising: a first member havinga first blade for pressing a boundary portion between the target shapeportion and one of the joint portions from one face of said metal sheetand from the side of said target shape portion; and a second memberhaving a second blade which approaches the joint portion from the otherface of the metal sheet, grips said boundary portion in association withsaid first blade in a thickness direction of the metal sheet and shearsthe metal sheet at said boundary portion to thereby cut said targetshape portion off the joint portion.
 2. The target shape portion cuttingapparatus according to claim 1, wherein said second member is supportedrotatably relative to said first member and is driven by a cylinder or amotor.
 3. The target shape portion cutting apparatus according to claim1, wherein said second member is moved by a cylinder or a motor in saidthickness direction of said perforated metal sheet relative to saidfirst member and cuts said target shape portion off the joint portion.4. The target shape portion cutting apparatus according to any one ofclaims 1 to 3, wherein said second member is thick enough to be able tobend the joint portion by pushing when cutting said target shape portionoff the joint portion.
 5. A robot mounting a target shape portioncutting apparatus for cutting a target shape portion off a joint portionin a metal sheet which has been worked such that the target shape isconnected to a base metal through one or a plurality of joint portionsby forming a hole at a region adjacent to the joint potion, said targetshape portion cutting apparatus comprising: a first member having afirst blade for pressing a boundary portion between the target shapeportion and one of the joint portions from one face of said metal sheetand from the side of said target shape portion; and a second memberhaving a second blade which approaches the joint portion from the otherface of the metal sheet, grips said boundary portion in association withsaid first blade in a thickness direction of the metal sheet and shearsthe metal sheet at said boundary portion to thereby cut said targetshape portion off the joint portion.
 6. The robot according to claim 5,wherein said second member is supported rotatably relative to said firstmember and is driven by a cylinder or a motor.
 7. The robot according toclaim 5, wherein said second member is moved by a cylinder or a motor inthe thickness direction of said perforated metal sheet relative to saidfirst member and cuts said target shape portion off the joint portions.8. A robot according to any one of claims 5 to 7, wherein said secondmember is thick enough to be able to bend each of said one or pluraljoint portions by pushing when cutting said target shape portion off thejoint portion.
 9. A method of cutting a target shape portion off a jointportion in a metal sheet, using a target shape portion cuttingapparatus, which has been worked such that the target shape is connectedto a base metal through one or a plurality of joint portions by forminga hole at a region adjacent to the joint potion, said target shapeportion cutting apparatus comprising: a first member having a firstblade for pressing a boundary portion between the target shape portionand one of the joint portions from one face of said metal sheet and fromthe side of said target shape portion; and a second member having asecond blade which approaches the joint portion from the other face ofthe metal sheet, grips said boundary portion in association with saidfirst blade in a thickness direction of the metal sheet and shears themetal sheet at said boundary portion to thereby cut said target shapeportion off the joint portion, and the method comprising: placing themetal sheet where said holes are formed on a mounting section whosesurface member is made of a soft material or a brush-like material softenough to be able to keep a plane posture of said target shape portionand said base metal sheet; inserting said second member of said targetshape portion cutting apparatus into the hole formed at a regionadjacent to the joint potion, and pressing said upper surface member ofsaid mounting section with a distal end portion of said second member;moving said target shape portion cutting apparatus forward to a positionwhere said first blade and said second blade can grip the joint portionfrom above and below, while pressing said mounting section with saidsecond member; pressing the first member against a top surface of saidtarget shape portion in such a way that said first blade of said firstmember positioned above the joint portion comes over said boundaryportion between said target shape portion and that joint portion; andmoving said second blade upward with respect to said first blade tothereby cut the joint portion by a shearing action.
 10. The methodaccording to claim 9, wherein said target shape portion cuttingapparatus is mounted on a robot and said method of cutting a targetshape portion off a joint portion is executed by an operation of therobot.
 11. An apparatus for cutting out a target shape portion from ametal sheet by shearing a joint portion at a region bordering on thetarget portion to cut out the target shape portion, said metal sheetbeing formed with said target shape portion, a remaining portionsurrounding said target shape portion and one or a plurality ofelongated joint portions joining said target shape portion with saidremaining portion, said apparatus comprising: a movable blade memberwhich is designed to move to a position below the joint portion; a fixedblade member for pressing the joint portion from above, said movableblade member being rotatable or linearly movable with respect to saidfixed blade member and having a movable blade having a predeterminedwidth and also a predetermined length equal to or longer than the widthof the joint portion, said fixed blade member having a block forpressing the joint portion and a fixed blade with a length equal to orlonger than the width of the joint portion, whereby, said apparatus,while being placed at a fixed position, rotates or linearly moves saidmovable blade member with respect to said fixed blade member once,thereby shearing the joint portion at a region bordering on the targetportion and bending a sheared-side end of the sheared joint portionupward.